Before, the history module fetched info about "modified records" from
sys_history+the authoritive user from a coupled sys_log entry.

Info about "insert" and "delete" was fetched from sys_log solely.

However, when using a scheduled cleanup task to truncate sys_log
then all history information is useless (see bug report).

The patch introduces a new RecordHistoryStore as an abstraction
for adding history entries (currently done solely within DataHandler).

It adds some additional, necessary SQL fields to sys_history to
store all information in there and creates an update wizard
to migrate all coupled sys_history/sys_log entries to a
new sys_history entry itself.

Additionally, the whole existing "RecordHistory" class is
now only necessary for fetching the so-called ChangeLog,
for a page or a specific record, and to do rollbacks, preparing
the history records so they can be worked on.

The whole logic for fetching the GET/POST parameters is moved
into the "ElementHistoryController", everything that is only possible
via Fluid is moved from the RecordHistory object and the
ElementHistoryController into the view.

Referencing from sys_log (Log module) into sys_history is
now done the other way around, storing information about
the corresponding history entry inside sys_log.
As a side-effect, sys_log should load faster.

Abstraction basis:
- sys_history is the only source of truth about the history of a record
- sys_log contains a reference to an history entry now
(inside sys_log.log_data) to link from the backend log module
- RecordHistoryStore exists for tracking changes to records
- RecordHistory is for retrieving, compiling the history/changelog and rollbacks
- ElementHistoryController is doing PSR-7 style request/response
handling and preparing data for the view
- Fluid is handling more view functionality now, removing
the need for doing <f:format.raw> everywhere in the templates.

Sidenotes:
* Data within sys_history is now stored as JSON, not serialized anymore
* Adding/deleting was previously stored in sys_log only, is now within sys_history
* Moving records is now tracked (but not evaluated yet)
* Highlight/Snapshot functionality within the Backend Module
was removed

This functionality is built so it can also be used within Extbase
persistence and in FE in general in a future iteration.